CN101092360A - Method for catalyzing and synthesizing tri-butyl citrate from methylal naphthalene sulfonic acid - Google Patents

Abstract

This invention discloses a method for catalytically synthesizing tributyl citrate by using naphthalenesulfonic acid/formaldehyde condensation compound as the catalyst by ester synthesis. The method comprises: performing ester synthesis by using naphthalenesulfonic acid/formaldehyde condensation compound as the catalyst, filtering after reaction, and vacuum-distilling to obtain tributyl citrate. The method has such advantages as high yield (94.4-99%), low catalyst consumption (0.37-1.85 wt. % of raw materials), mild reaction conditions, short reaction time, recoverable catalyst, and no need for toxic toluene solvent. Reactant n-butanol can be directly used as the water-carrying agent.

Description

A kind of method with naphthene sulfonic acid methylal catalysis synthesizing citric acid tri-n-butyl

Technical field

The present invention relates to the organic chemistry synthesis technical field, specifically a kind of method with naphthene sulfonic acid methylal catalysis synthesizing citric acid tri-n-butyl.

Background technology

Tributyl citrate is nonpoisonous and tasteless " green " environmentally-friendly plastic softening agent, be widely used in food and medical instrumentation package, makeup, daily necessities, toy, military supplies etc., have that consistency is good, plasticizing efficiency is high, nontoxic, easily by advantage such as biological degradation and volatility be little, winter hardiness, photostabilization and have excellent water-resistance, and mould resistance is arranged in resin, do not grow mould.The shared goods hardness that improves of tributyl citrate and other non-toxic plasticizers, especially more suitable to soft fiber ether.Simultaneously, tool improves the nitrocotton anti-uv-ray, and is the solvent of multiple spices, also can be used for the defoamer of protein-based solution.Therefore, tributyl citrate becomes present conventional plasticizers phthalate " green " substitute.The traditional method of synthesizing citric acid tri-n-butyl is to do catalyzer [Song Qihuang chief editor with the vitriol oil, fine chemistry industry technology, Beijing: Chemical Industry Press, 1995:95], this catalyzer exists side reaction many, refining difficulty, equipment corrosion is serious, and the aftertreatment complexity produces industry " three wastes ", shortcomings such as contaminate environment, its application have been subjected to very big restriction.Some catalyzer that grew up afterwards all have catalytic activity preferably as being catalyzer [Xie Wenlei etc., Speciality Petrochemicals, 1998, (4): 7-9] with the tosic acid to this reaction, but catalyzer costs an arm and a leg, and can not recirculation use.

Summary of the invention

The objective of the invention is provides a kind of eco-friendly, economic heterogeneous catalysis to prepare the method for tributyl citrate at the deficiencies in the prior art, is that catalyzer solves the existing problem of prior art with the naphthene sulfonic acid methylal.

The present invention solves this technical problem by the following technical programs: be catalyzer with the naphthene sulfonic acid methylal in the ester building-up process, after reaction finishes, filter, filtrate is handled through normal pressure, underpressure distillation can obtain tributyl citrate, the naphthene sulfonic acid methylal that reaction end after-filtration goes out can be recycled, and activity remains unchanged substantially.

Reaction expression of the present invention is as follows:

The present invention includes following concrete steps:

The preparation of the 1st step naphthene sulfonic acid methylal

5～20g naphthalene is heated to 160 ℃, the vitriol oil of slow Dropwise 5～20ml behind 120～160 ℃ of following heated and stirred 1～6h, is cooled to 90～120 ℃ more then, after adding 2～5ml water, drip formaldehyde solution 10～20ml, keep 100 ℃ of heating 4～8h, get black solid, adding boiling water then washs, suction filtration, 100～140 ℃ of oven dry get the naphthene sulfonic acid methylal;

The 2nd step esterification

In having the 100mL three-necked bottle of induction stirring, thermometer, reflux condensing tube, water trap, add 0.1～0.15mol citric acid, 0.4～0.6mol propyl carbinol and 0.1～0.5g naphthene sulfonic acid methylal, reflux stirs, the water that reaction is produced is told from water trap, reaction to the anhydrous water trap that enters again stops, and gets the thick product of tributyl citrate;

The separation of the 3rd step catalyzer and the purifying of product

Thick product is filtered, and the naphthene sulfonic acid methylal that leaches is directly used in down secondary response, and filtrate is reclaimed excessive propyl carbinol through the normal pressure distillation, be cooled to room temperature then, underpressure distillation, the cut of 178～180 ℃/400Pa of collection obtains water white product tributyl citrate.

Described naphthene sulfonic acid methylal consumption accounts for 0.37～1.85% of reaction raw materials gross weight.

Compared with prior art, advantage of the present invention is: (1) productive rate height is up to 99.0%; (2) catalyzer is cheap, and catalyst levels is little, accounts for 0.37～1.85% of reaction raw materials gross weight; (3) reaction conditions gentleness, the reaction times is short; (4) catalyzer can be recycled; (5) directly make the band aqua, avoided using deleterious toluene etc. with the reactant propyl carbinol.

Embodiment

Below will the present invention is further elaborated by specific embodiment:

Embodiment 1

The preparation of the 1st step naphthene sulfonic acid methylal:

The 5g naphthalene is heated to 160 ℃, slowly drips the vitriol oil of 15ml then, behind 140 ℃ of following heated and stirred 4h, be cooled to 100 ℃ again, behind the adding 2ml water, drip formaldehyde solution 15ml, keep 100 ℃ of heating 5h, get black solid.Add boiling water then and wash, suction filtration, 110 ℃ of oven dry get the naphthene sulfonic acid methylal;

The 2nd step esterification

In having the 100ml three-necked bottle of induction stirring, thermometer, reflux condensing tube, water trap, add 0.1mol citric acid, 0.45mol propyl carbinol and 0.3g naphthene sulfonic acid methylal, reflux stirs, the water that reaction is produced is told from water trap, reaction to the anhydrous water trap that enters again stops, and gets the thick product of tributyl citrate;

The separation of the 3rd step catalyzer and the purifying of product

Thick product is filtered, and the naphthene sulfonic acid methylal that leaches is directly used in down secondary response, and filtrate is reclaimed excessive propyl carbinol through the normal pressure distillation, is cooled to room temperature then, underpressure distillation, and the cut of 178～180 ℃/400Pa of collection gets water white transparency product tributyl citrate.Productive rate is 99.0%.

Embodiment 2-4

Except for the following differences, all the other are identical with embodiment 1, are 0.3g at naphthene sulfonic acid methylal consumption, and the citric acid consumption is 0.1mol, and the propyl carbinol consumption the results are shown in Table 1 to the influence of reaction.

Table 1

Embodiment	Acid alcohol is than (mole)	Productive rate/%
			2 3 4	1∶4.0 1∶5.0 1∶6.0	98.2 98.9 98.6

Embodiment 5-8

Except for the following differences, all the other are identical with embodiment 1, and naphthene sulfonic acid methylal consumption the results are shown in Table 2 to the influence of reaction

Table 2

Embodiment	Catalyst levels/g	Productive rate/%
			5 6 7 8	0.1 0.2 0.3 0.5	97.3 98.4 99.0 98.5

Embodiment 9-12

Except for the following differences, all the other are identical with embodiment 1, and catalyst recirculation uses the influence to reaction to the results are shown in Table 3

Table 3

Embodiment	The catalyst recirculation access times	Productive rate/%
			9 10 11 12	1 2 3 4	98.9 97.8 96.9 94.4

Claims (2)

1, a kind of method with naphthene sulfonic acid methylal catalysis synthesizing citric acid tri-n-butyl is characterized in that: make catalyzer with the naphthene sulfonic acid methylal in the ester building-up process, after filtration, gained filtrate promptly obtained tributyl citrate through underpressure distillation after reaction finished; Its concrete steps are:

The preparation of the 1st step naphthene sulfonic acid methylal

5～20g naphthalene is heated to 160 ℃, the vitriol oil of slow Dropwise 5～20ml behind 120～160 ℃ of following heated and stirred 1～6h, is cooled to 90～120 ℃ more then, after adding 2～5ml water, drip formaldehyde solution 10～20ml, keep 100 ℃ of heating 4～8h, get black solid, adding boiling water then washs, suction filtration, 100～140 ℃ of oven dry get the naphthene sulfonic acid methylal;

The 2nd step esterification

In having the 100mL three-necked bottle of induction stirring, thermometer, reflux condensing tube, water trap, add 0.1～0.15mol citric acid, 0.4～0.6mol propyl carbinol and 0.1～0.5g naphthene sulfonic acid methylal, reflux stirs, the water that reaction is produced is told from water trap, reaction to the anhydrous water trap that enters again stops, and gets the thick product of tributyl citrate;

The separation of the 3rd step catalyzer and the purifying of product

Thick product is filtered, and the naphthene sulfonic acid methylal that leaches is directly used in down secondary response, and filtrate is reclaimed excessive propyl carbinol through the normal pressure distillation, be cooled to room temperature then, underpressure distillation, the cut of 178～180 ℃/400Pa of collection obtains water white product tributyl citrate.

2, method according to claim 1 is characterized in that described naphthene sulfonic acid methylal consumption accounts for 0.37～1.85% of reaction raw materials gross weight.